NEW YORK (CBSNewYork) — There is once again a high terror alert in New York City. Mayor Michael Bloomberg and Police Commissioner Ray Kelly said Tuesday they are taking no chances that an attack similar to the Boston Marathon bombings could happen here.

The city’s anti-terrorism slogan has always been if you see something say something, and people have been responding in droves, keeping the NYPD busy with dozens and dozens of reports of suspicious packages, CBS 2’s Marcia Kramer reported.

“We asked the public to be vigilant, particularly as far as packages are concerned, and in doing that and after yesterday’s events we anticipated that it would be an increase in reports of suspicious packages and indeed there was,” Kelly said.

In the 24 hours after the Boston attack, NYPD bomb squad detectives responded to 77 reports of suspicious packages — the norm is 21 — all across the city. It is evidence of the alarm New Yorkers are feeling these days.

“We have increased our coverage in the subways. We have the second largest transit system in the world. Five million people a day travel the system. We are doing bag searches in the system,” Kelly said.

Police set up security stations, pulling commuters aside for random checks for explosives in bags.

“I’m not really even sure what they just did there, but if they just tried to take a sample off my strap, I’m not sure that that’s going to detect any type of device,” commuter John Ralph said.

“Just the world we live in I guess. We have to adapt to it,” commuter Michael Hill added.

Bloomberg said security in New York City will remain tight until authorities know more about what happened in Boston.

“For more than 230 years Americans have fought and died to defend the freedoms that shaped the Declaration of Independence. No foreign power, no domestic faction and no terrorist group has even stopped the march of freedom in this country — and it never will,” Bloomberg said.

The NYPD isn’t aware of any specific threats against the city after the explosions at the Boston Marathon, but Bloomberg stressed the city is taking precautions.

“Since yesterday afternoon, we have fully mobilized our resources to protect New Yorkers from any related threats that might emerge,” Bloomberg told reporters Tuesday during a news conference.

NYC To Stay At Heightened Alert Level

“In this post 9/11 world, we have to be concerned and we are concerned,” Kelly said at Tuesday’s briefing.

Areas like Times Square, Rockefeller Center, Grand Central, the Empire State Building and the United Nations were being especially monitored, police said. As CBS 2’s Derricke Dennis reported, the city’s guard was up at the World Trade Center site, across the George Washington Bridge, and at places such as the popular Mandarin Hotel in Columbus Circle, where an event was held Tuesday night.

The city also has two major events coming up this weekend — a 5K run/walk to the Sept. 11 Memorial and Museum Sunday and a 4-mile race in Central Park.

“We are certainly re-evaluating them in light of the event that took place yesterday,” Kelly said. “There are certain events that are going to be open just by their very nature. Marathons are 26 miles long so there are points of vulnerability. By definition they’re are going to be.”

“We must remain vigilant in the future and we are vigilant,” Bloomberg said. “The fact is there remain people who want to attack us and the moment we let our guard down, the moment we get complacent, the moment we allow special interests to shape our security strategies is the moment the terrorists are waiting for.”

NYC To Stay At Heightened Alert Level

Bloomberg said he called Boston Mayor Thomas Menino Monday and told him “New York City would do anything possible to support Boston now and in the days ahead.”

He said he has also ordered flags to be flown at half-staff across the city and said Boston’s flag is flying at half-staff at City Hall.

“We stand shoulder to shoulder with our friends in Boston as all Americans do,” Bloomberg said.

“We’ve had 16 plots against the city since September 11, 2001,” he said. “In the last six months, we’ve had five individuals either arrested or convicted for plotting against New York City, so we believe the threat has remained constant since 9/11.”

“There’s nothing we know that we think is going to happen, but we have to be prepared,” Bloomberg said.

A police K-9 unit dog sniffs newspaper boxes for explosives outside of Penn Station on April 16, 2013 in New York City. (Photo by John Moore/Getty Images)

Governor Andrew Cuomo has also ordered state agencies to operate on heightened alert and directed that flags on state government buildings be flown at half-staff on Wednesday.

“I join with my fellow New Yorkers and Americans in mourning the loss of the innocent lives that were taken in yesterday’s terrorist attack at the Boston Marathon,” Cuomo said. “I extend my deepest sympathy to the family and friends of the victims, as well as the residents of Boston.”

The Metropolitan Transportation Authority has also beefed up security within the subways and on the Long Island Rail Road and Metro-North.

Commuters at the Hicksville LIRR station Tuesday said they had some anxiety heading into the city, but refused to let the Boston tragedy paralyze them with fear.

“It’s tragic, but I’ve got to do what I have to,” one commuter told WCBS 880 Long Island Bureau Chief Mike Xirinachs.

“Life has to go on, but you have to be vigilant,” said another.

But passengers were also on guard.

On Alert At Penn Station

“I keep my eyes open. They make announcements over the loudspeaker all the time. ‘If you see any suspicious activities, report it to someone of authority,'” a commuter at Penn Station told WCBS 880 reporter Sean Adams.

“I’ve got a watchful eye, but I feel OK. Sad, really sad, but it’s a different world,” said another who added that 9/11 never leaves you.

On Alert On The LIRR

On Tuesday morning, Bloomberg and his security detail took the subway to show New Yorkers that it’s safe.

“We won’t let the attack in Boston keep us from our normal daily routines or enjoying the city that we love and that we so painstakingly built,” Bloomberg said. “That’s what we have to do: go about our day, keep the victims of this awful tragedy in our thoughts and our prayers. Go about our business. Let’s not forget what happened in the past and let’s prepare for the future.”